If an extension was filed, the IRS would know that so there isn't anything magical you need to do.

Thank you for your response. Although I found something to indicate an extension was filed before. In Part VII click Quick Zoom to Form 4868 Electronic Filing Information Worksheet,, there are 3 questions related to that: Form 4868 accepted and a checkmark, date form 4868 was efiled, and date Firn 4868 was accepted. But thanks anyway.  

Results may vary for any state returns involved.